Subject: [homenet] WGLC Comment on HNCP

From: Margaret Cullen <[email-masked]>
Date: Mon, 20 Jul 2015 04:49:53 +0200

I have reviewed the HNCP protocol, and I only have one issue that needs to be resolved before I will support submitting it to the IESG for publication. 

The current version of the HNCP document addresses the earlier concern I raised about the specification of a new routing protocol inside of HNCP.  However, in addressing that concern, it raises a new issue.  In section 11, the document currently says:

"[HNCP Routers] MUST implement and run a routing protocol appropriate for the given link type on all of the interfaces it sends and receives HNCP traffic on."

Saying that HNCP Routers MUST run "a routing protocol" is insufficient to ensure interoperability between different HNCP Router implementations.  There are (at least) two options for how to fix this:

(1) Specify a single HNCP routing protocol, or

(2) Specify a routing protocol selection/negotiation mechanism, and a single mandatory-to-implement protocol that will be used when there is no preferred protocol that is implemented by all of the HNCP routers on a given link.

The first choice has the benefit of simplicity (no negotiation mechanism needed, no need to implement more than one protocol), but it lacks the flexibility and future extensibility of a negotiation mechanism combined with one mandatory-to-implement choice.

Margaret